Process of regrigeration.



E. A. W. JEFFERIES.

PROCESS OF REFRIGERATION.

APPLICATION FILED JAN. 26. I915.

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Patented Apr. 30, 1918.

EBENEZER "W, JEFFERIES, 0F WGECESTER, MASSACHUSETTS, ASSIGNOE T63 JEFFERIES NORTON CQEPQRATIQN, A CORPORATION" OF DELAWARE,

PROCESS OF REFRIGERATION.

Specification. of Letters Patent.

Patented 11918,

Application filed January 26, 1915. Serial No. 4,536.

To all whom it may concern:

Be itknown that I, EnnNnzn-u A. W. Jarrnnms, a citizen of the United States, residing at Worcester, in the county of Worcester and Commonwealth of Massachusetts, have invented. a new and useful Improvement in Processes of Refrigeration, of which the following is a specification accompanied by drawings, forming a part of the same.

The present invention relates in general to processes of refrigeration, and has particular reference to improvements in processes of this class Which, in general, contemplate the attainment of extremely low temperatures by the use of a gaseous worlc ing fluid. The low temperatures attained in the present process, in common. with the processes previously practised, ma 1 be used, if desired, in securing extreme refrigerative effects; or the process may be carried on for the purpose of liquefying, in Whole or in part, the gas, and if desired, this liquefaction, if the gas be a mixed. gas, may be employed in connection with suitable distillation agencies to effect the separation of the gas into its constituent elements. Moreover, as will be shown, the process may with advantage be utilized for the cheap and efficient production of power, in a form available for the production of useful. work.

The present invention is chiefiy concerned with the employment of certain. steps designed to recover power from the gases liquefied in the process, The power thus recovered may be utilized in driving or assisting in driving the devices used for the initial compression of the gas, Wherehya marked increase in efliciency and fuel economy, over other processes of this char acter now in use, is attained. Other objects and advantages will appear from the following description of my process, and of one arrangement of apparatus by which said process may be carried out, such apparatus being illustrated diagrammatically in the single figure of the accompanying drawings,

It is to be understood, however, that the carrying out of my invention isnot confined to the employment of the herein described, or any other particular arrangement of apparatus, nor to the herein described methods of operating such apparatus, except in so far as specified in the appended claims; the drawings and description being illustrative merely of one Way of applying the principles of my invention,

As heretofore practised, processes involving the liquefaction of gases have been characterized by the releaseof the condensed fluid from pressure, thereby permitting spontaneous reevaporation of said condensed fluid, with a resulting high refrigerative edect during such revaporation. My invention differs essentially from such processes, in

thatthe condensed fluid instead of being re illustration of an arrangement of apparatus for carrying out the process, together with the several steps of the process, Will now be described in detail.

Referring by way of example, to the accompanying drawings, the gas dealt with in my process is compressed in a compressor 1, and is then led through an ordinary Water cooling device 2, for the purpose of extracting the heat of compression therefrom. The cooling device 2 communicates by a passage 3 of a heat exchanger designated as a Whole by the numeral 4, with a vessel 5, serving as a container for a quantity of the same gas in a liquid state. There is no escape for the liquid from the vessel 5 to the return circuit of the system except through a pump 6, which delivers the liquid into said return circuit through a refrigerating coil 7, at a pressure higher than the pressure in the pussage 3, it being understood that in common with other refrigeration processes of this class, my lnventlon contemplates the con tinuous liquefaction of the cooled. compressed gas While traversing the passage of the heat exchanger 4, to replenish the supply of liquid in the vessel 5, as fast as the same is pumped out,

The fluid leaving the coil 7 enters a pass'uge 8 forming another part of said heatcxchanger 4, wherein it is evaporated and has its temperature raised by interchange of heat with the gas in the passage 3 co1n-' ing in from the compressor 1. The pressure prevailing in passage 8 and coil 7 is obviously due to the resistance imposed 5 against outflow 'ofvapor from the upper end of said passage; in forcin liquid into the coil 7, the pump 6 must put it under sufficient pressure to overcome the pressure thus maintained in passage 8, which, as above stated, is higher than the pressure revailing in passage 3. The heat exchange between the fluids in passages 3 and 8, in a manner similar to that well-known in apparatus of this character, entails the discharge of high pressure fluid from the top or warm end of passage 8 at substantially the temperature of the gas entering the interchanger at the top or warm end of passage 3; the substantial equalization of temperatures at any given level by heat interchange between the two passages 3 and 8, is contemplated, and in common with other apparatus of this character, the temperatures are lower the lowerthe level reached in said interchanger. The passage '8 communicates witha heating device 9, wherein the whole or a portion of the gas evaporated from the liquid leaving the pumn 6, has its temperature further increased, prior to its use in a hot expansion engine or motor 10, which may be operatively connected to. drive the compressor 1. Part of the gas passing through the exchanger in passage '3 may be used 1n a cold expansion or refrigerating engine 11, which may be operatively connected to the compressor 1 and motor 10. Said engine 11 exhausts intothe cold end of a passage 12 which forms a third part vof the heat exchanger 4. If preferred, that portion of the gas used in said refrigerating engine 11 may be taken from the passage 8, after revaporation at the increased pressure, instead of from the passage 3. The gases exhausted from said engine 11, together with the exhaust gas from the motor may ultimately be returned to the-inlet of the compressor through pipes 13 and 14, respectively, recompressed in said compressor, and passed again through the sa; 1e circuit.

Assuming the establishment of the conditions illustrated in the figure, wherein the broken lines denote the presence of liquefied gas in' vessel 5 and coil 7, it will be clear that the cold expansion engine 11, passage 12, and their several interconnections constitute an external cooling agency, the provision of which, in one'form or another, is requisite to the liquefaction of the gas traversing passage 3 from'the compressor 1 to the vessel 5. As set forth above, the increase inrpressure upon the liquid effected by the pump 6, imparts to the outgoing gas evaporated from such liquid, the ability to $5 absorb heat usefully-and thus to attain more energy than is possessed by the same quantity of gas brought into the exchanger 4 at the original pressure by passage 3.

The amount which. the pressure is increased by pump 6 governs the amount of available energy contained in the gas leaving the exchanger on its way to the heater 9. The cold expansion engine 11 also contributes some energy, and the balance, to make up the total required to operate the system, may be supplied inpart at least, by the addition of heat to the outgoing gas, at the increased pressure, in the heater 9, cansin the hot expansion motor 10 to deliver a 'arge portion of the power required for operating the entire system.

It will be seen, therefore, that the most effective use of the present process contemplates an increase, rather than a decrease in the pressure of the liquefied gas; an evaporation of the same during its return through the exchanger under such increased pressure; the addition of heat to said products of evaporation by external means, still further increasing its available energy over that absorbed in compressing the incoming gas; and the recovery of power therefrom to perform useful work. The heat required for vaporizing the liquid, so placed under increased pressure, and for raising the temperature of the vapor in the exchanger is derived from an interchange of heat with the fluid which is passing through earlier stages in the process, and from heat leak- .ing into the exchanger from the 'atmosphere; the surplus heat required to raise the temperature of the said vapor above that of said incoming fluid, in order still. further to increase the available energy contained in said vapor over that absorbed in compressionlof said incoming fluid, is derived from exterior sources, such as steam, combustible fuel,,or waste heat.

I am aware that the process herein described can be most usefully employed only with fluids whose boiling points are .below ordinary atmospherictemperatures,

that is, with fluids which are gaseous in their free state. I am further aware that raising, the pressure of the liquefied fluid before evaporation works a certain disadvantage by reducing its latent heat of vaporization, and in consequence, decreasing the refrigerative power of a given quantity of such fluid. But I find that such disadvantage is not only completelycompensated for, but is considerably outweighed or overbalanced in economic result, by the advantage herein set forth, namely, the recovery of power, capable of being applied if desired to the production of additional refrigeration and to operating the mechanism of the process in a more efficient manner than heretofore.

Although I have described the process actually practiced according to the present inheadset vention, namely, increasing the pressure on the liquefied fluid before revaporation for the purpose of ultimate power economy, yet

it will be .obvious that the same purpose may be accomplished, in less de 'ee, ifthe pressure is merely sustained instead of being released in the usual manner; or, the pressure may even be reduced and still carry out the purpose of this invention by retaining suflicient pressure to permit of absorbing heat usefully for the production or recovcry of power.

It is to be understood that the process, as herein described, does not of necessity entail either the complete or the absolute liquefaction of the gaseous workingfluid, and that the terms liquefaction liquid and liquefied as used herein and fin the appended claims apply as well to a condition of the fluid wherein density and temperature it substantially approaches the liquid state. In such a condition said fluid is susceptible to a pressure increase by the expenditure of an almost negligible amountof power,

which, together with the power required for initial compression is largely recoverable in the efficient manner hereinbefore set forth.

In the application of the foregoing "new principles, which differ radically and essentially from the principles underlying previous processes of this class, it is to be understood that. my invention is in nosense limited to equivalents of the apparatus shown, said showing being wholly diagrammatic and illustrative and adopted solely forthe purpose of simplifying the explanation'of said broadly new principles.

I claim,

1. In a processof refrigeration, employing a" working fluid which is gaseous in its free state, the progressive liquefaction of said gaseous working fluid, the placing of the liquid portion thus formed under a pres sure greater than that at which it was liquefied, the vaporization of said liquid portion, under its increased pressure, by heat interchange with the gaseous portion of the working fluid which is aboutto under o said progressive liquefaction, and the utilization of the vapor thus produced to furnish power.

2. In a process of refrigeration, employing a working fluid which is gaseous in its free state, the progressive liquefaction of .said gaseous working fluid, increasing the pressure upon the liquid portionthus formed, vaporizing said liquid portion under its increased pressure by heat interchange with the gaseous portion of the working fluid which is about to undergo said progressive liquefaction, heating the evaporate from said high pressure liquid portion and expanding said heated evaporate in an expansion engine.

3. In a process of refrigeration, employing 'a working fluid which is gaseous in its free state, the progressive liquefaction of said gaseous working fluid, increasing the pressure on the liquid portion thus formed, and circulating the evaporate from said liquid portion, under. saidhigher pressure, in heat exchangin relation to the gaseous portion ofthe wor ing fluid which is about to undergo said progressive liquefaction.

4. In a process'of refrigeration, employing a working fluid which is gaseous in its free state, the progressive liquefaction of said gaseousworking fluid, vaporizin the liquid portion thus formed under a sufficient pressure to enable the evaporate to perform useful work by expansion, and circulating said evaporate, under such pressure, inheat exchanging relation to the gaseous portion of the working fluid which is about to undergo said progressive liquefaction.

5. In a process of refrigeration, employing a working fluid which is gaseous in its free state, the progressive liquefaction, under pressure, of said working fluid, the vaporization of the liquid portion thus formed while maintained under suficient pressure to enable the evaporate to absorb heat usefully,

circulating said evaporate in heat exchangliquefied, circulating said evaporate in heat exchanging relation to the gaseous portion of the working fluid which is about to undergo said progressive liquefaction, addingexternal heat to said evaporate, and recovering power from said heated evaporate to perform useful work.

7. In a process of refrigeration, employing a working fluid which is gaseous in its free state, the'progressive liquefaction of said gaseous working fluid, evaporating the liquid portion thus formed at a pressure greater than that at which the fluid was liquefied, cooling the gaseous portion of the working fluid which is about to undergo said progressive liquefaction by heat interchange with said high pressure evaporate, and expanlqing said evaporate to perform useful wor 8. In a process of refrigeration, employing a working fluid which is gaseous in its free state, the progressive cooling and liquefaction of said gaseous working fluid by heat interchange with a portion thereof which has been expanded, the raising of the pressure on, the liquid portion thus formed, and the circulation of the evaporate from said liquid portion, under such increased pressure, in heat exchanging relation to the gaseous working fluid which is being cooled and liquefied.

S). In a process of refrigeration, employing a working fluid which is gaseous in its free state, the progressive cooling and liquefaction of said gaseous working fluid by heat interchange with another portion thereof which has been expanded, the raising of the pressure on the liquid portion thus formed, the circulation of the evaporate from said liquid portion, under such increased pressure, in heat exchanging relation to the gaseous working fluid which is being cooled and liquefied, the addition of heat to said high pressure evaporate, and the expansion thereof to perform useful work.

10. In a process of the character set forth,

employing a working fluid which is gaseous in its free state, the liquefaction of said working fluid and the increase of pressure thereon while in the liquid state in advance of its circulation, in countercurrent, to the working fluid which is about to undergo liquefaction.

11. In a process of the character set forth, employing a working fluid which is gaseous in its free state, the liquefaction and subsequent vaporization of said fluid, and the increase of pressure thereon while in the liquid state in advance of the circulation of the products of said vaporization, in countercurrent, to the working fluid which is about to undergo liquefaction.

EBENEZER- A. W. JEFFERIES. .lVitnesses PENELOPE CoMBERBAoH, NELLIE WHALEN. 

